/drivers/bcma/README

 1Broadcom introduced new bus as replacement for older SSB. It is based on AMBA,
 2however from programming point of view there is nothing AMBA specific we use.
 3
 4Standard AMBA drivers are platform specific, have hardcoded addresses and use
 5AMBA standard fields like CID and PID.
 6
 7In case of Broadcom's cards every device consists of:
 81) Broadcom specific AMBA device. It is put on AMBA bus, but can not be treated
 9   as standard AMBA device. Reading it's CID or PID can cause machine lockup.
102) AMBA standard devices called ports or wrappers. They have CIDs (AMBA_CID)
11   and PIDs (0x103BB369), but we do not use that info for anything. One of that
12   devices is used for managing Broadcom specific core.
13
14Addresses of AMBA devices are not hardcoded in driver and have to be read from
15EPROM.
16
17In this situation we decided to introduce separated bus. It can contain up to
1816 devices identified by Broadcom specific fields: manufacturer, id, revision
19and class.